A search engine is a tool that identifies documents, typically stored on hosts distributed over a network, which satisfy search queries specified by users. Web search engines work by storing information about a large number of documents (such as web pages) which they retrieve from the World Wide Web (WWW) via a web crawler. Such documents are downloaded by the web crawlers during crawling sessions for purposes of indexing. However, some websites may have several equivalent domain names. As a result, a respective document of a specified website that is associated with several equivalent domain names may be indexed based on several URLs that correspond to the various equivalent domain names. Thus, it may be advantageous to enable a website owner to designate a preferred domain name for a website that is associated with more than one domain name.
Like reference numerals refer to corresponding parts throughout the drawings.